Description of the problem

Documentation for grdcontour uses the common alias {G} which should be a custom one for 'label_placement'. But this incorrectly points to the common alias for color (G):

The fix shouldn't be too hard, just need to change the line {G} above to the full documentation at https://docs.generic-mapping-tools.org/6.1/grdcontour.html#g.

label_placement : str
    ``[d|f|n|l|L|x|X]params``.
    The required argument controls the placement of labels along the quoted lines. Choose among five controlling algorithms:
    ...

Make sure you wrap the docstring to 79 characters as per #384!

System information

Please paste the output of python -c "import pygmt; pygmt.show_versions()":

pygmt: v0.2.0